Magnetoresistive device and method of manufacturing same

ABSTRACT

A magnetoresistive-based device and method of manufacturing a magnetoresistive-based device using one or more hard masks. The process of manufacture, in one embodiment, includes patterning a mask, after patterning the mask, etching (a) through a first layer of electrically conductive material to form an electrically conductive electrode and (b) through a third layer of ferromagnetic material to provide sidewalls of the second synthetic antiferromagnetic structure. The process further includes providing insulating material on or over the sidewalls of the second synthetic antiferromagnetic structure and, thereafter, etching through (a) a second tunnel barrier layer to provide sidewalls thereof, (b) a second layer of ferromagnetic material to provide sidewalls thereof, (c) a first tunnel barrier layer to provide sidewalls thereof, and (d) a first layer of ferromagnetic material to provide sidewalls of the first synthetic antiferromagnetic structure.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/855,984, filed Dec. 27, 2017, which is a divisional of U.S. patentapplication Ser. No. 15/630,377, filed Jun. 22, 2017 (now U.S. Pat. No.9,865,804), which is a divisional of U.S. patent application Ser. No.15/081,397, filed Mar. 25, 2016 (now U.S. Pat. No. 9,698,341), which isa divisional of U.S. patent application Ser. No. 14/845,697, filed Sep.4, 2015 (now U.S. Pat. No. 9,306,157), which is a divisional of U.S.patent application Ser. No. 14/264,520, filed Apr. 29, 2014 (now U.S.Pat. No. 9,166,155), which is a divisional of U.S. patent applicationSer. No. 13/830,082, filed Mar. 14, 2013 (now U.S. Pat. No. 8,747,680).This non-provisional application and the '984, '377, '397, '697, '520and '082 applications claim priority to and the benefit of U.S.Provisional Application No. 61/682,860, filed Aug. 14, 2012.

TECHNICAL FIELD

The exemplary embodiments described herein relate tomagnetoresistive-based devices and methods of manufacturingmagnetoresistive-based devices.

BACKGROUND

Magnetoresistive-based devices, spin electronic devices, and spintronicdevices are synonymous terms for devices that make use of effectspredominantly caused by electron spin. Magnetoresistive-based devicesare used in numerous information devices to provide non-volatile,reliable, radiation resistant, and high-density data storage andretrieval. The numerous Magnetoresistive-based devices include, but arenot limited to, Magnetoresistive Random Access Memory (MRAM), magneticsensors, and read/write heads for disk drives.

Typically an MRAM includes an array of magnetoresistive memory elements.Each magnetoresistive memory element typically has a structure thatincludes multiple magnetic layers separated by various non-magneticlayers, such as a magnetic tunnel junction (MTJ), and exhibits anelectrical resistance that depends on the magnetic state of the device.Information is stored as directions of magnetization vectors in themagnetic layers. Magnetization vectors in one magnetic layer aremagnetically fixed or pinned, while the magnetization direction ofanother magnetic layer may be free to switch between the same andopposite directions that are called “parallel” and “antiparallel”states, respectively. Corresponding to the parallel and antiparallelmagnetic states, the magnetic memory element has low and high electricalresistance states, respectively. Accordingly, a detection of theresistance allows a magnetoresistive memory element, such as an MTJdevice, to provide information stored in the magnetic memory element.There are two completely different methods used to program the freelayer: field-switching and spin-torque switching. In field-switchedMRAM, current carrying lines adjacent to the MTJ bit are used togenerate magnetic fields that act on the free layer. In spin-torqueMRAM, switching is accomplished with a current pulse through the MTJitself. The spin angular momentum carried by the spin-polarizedtunneling current causes reversal of the free layer, with the finalstate (parallel or antiparallel) determined by the polarity of thecurrent pulse. The memory elements are programmed by the magnetic fieldcreated from current-carrying conductors. Typically, twocurrent-carrying conductors, the “digit line” and the “bit line”, arearranged in cross point matrix to provide magnetic fields forprogramming of the memory element. Because the digit line usually isformed underlying the memory element so that the memory element may bemagnetically coupled to the digit line, the interconnect stack thatcouples the memory element to the transistor typically is formed, usingstandard CMOS processing, offset from the memory element.

Efforts have been ongoing to improve scaling, or density, of MTJelements in an MRAM array. However, such efforts have included methodsthat use multiple masking and etching steps that consume valuable realestate in the MRAM device. Because an MRAM device may include millionsof MTJ elements, such use of real estate in the formation of each MTJelement can result in a significant decrease in the density of the MRAMdevice.

Accordingly, there is a need for a method of manufacturing amagnetoresistive-based device including patterning a magnetic tunneljunction and an electrode coupled thereto. Furthermore, other desirablefeatures and characteristics of the exemplary embodiments will becomeapparent from the subsequent detailed description and the appendedclaims, taken in conjunction with the accompanying drawings and theforegoing technical field and background.

BRIEF SUMMARY

Methods are provided for manufacturing a magnetoresistive-based deviceusing more than one hard mask.

In an exemplary embodiment, a method of manufacturing amagnetoresistive-based device having magnetic material layers formedover a first electrically conductive layer, the magnetic materialslayers including a tunnel barrier layer formed between a first magneticmaterials layer and a second magnetic materials layer, comprisespatterning a first hard mask over the second magnetic materials layer;removing the second magnetic materials layer unprotected by the firsthard mask, to form a second magnetic materials, respectively; patterninga second hard mask over the tunnel barrier layer, the first hard mask,and sides of the second magnetic materials; and removing the tunnelbarrier layer and the first magnetic materials layer unprotected by thesecond hard mask to form a tunnel barrier and first magnetic materials.

In another exemplary embodiment, a method of manufacturing amagnetoresistive-based device having a magnetic material layer formedover a first electrically conductive layer, the magnetic materialslayers including a tunnel barrier layer formed between a first magneticmaterials layer and a second magnetic materials layer, comprises etchinga portion of the second magnetic materials layer unprotected by a firsthard mask to form a second magnetic materials, respectively; patterninga second hard mask over the tunnel barrier layer, the first hard mask,and sides of the second magnetic materials; and removing the tunnelbarrier layer and the first magnetic materials layer unprotected by thesecond hard mask to form a tunnel barrier and second magnetic materials,wherein the first hard mask comprises a second electrode.

In yet another exemplary embodiment, a method of manufacturing amagnetoresistive-based device having magnetic materials layers formedbetween a first electrically conductive layer and a second electricallyconductive layer, the magnetic materials layers having a tunnel barrierlayer formed between a first magnetic materials layer and a secondmagnetic materials layer, comprises forming a first hard mask layer overthe second electrically conductive layer; patterning a first photoresist over the first hard mask layer; etching the first hard mask layerresulting in a first hard mask between the first photo resist and thesecond electrically conductive layer; etching the second electricallyconductive layer resulting in a second electrically conductive electrodebetween the first hard mask and the second magnetic materials layer;etching the second magnetic materials layer resulting in a secondmagnetic materials between the second electrically conductive electrodeand the tunnel barrier layer, the first hard mask, the secondelectrically conductive electrode, and the second magnetic materialsdefining a side; depositing a second hard mask layer over the tunnelbarrier layer, the first hard mask, and the side; patterning a secondphoto resist on the second hard mask and over the first hard mask layer;etching the second hard mask layer resulting in a second hard mask;etching the tunnel barrier layer resulting in a tunnel barrier betweenthe second magnetic materials and the first magnetic materials layer;etching the first magnetic materials layer resulting in a first magneticmaterial between the tunnel barrier and the first electricallyconductive layer; and etching the first electrically conductive layerresulting in a first electrode adjacent the first magnetic materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be described in conjunction withthe following drawing figures, wherein like numerals denote likeelements, and

FIGS. 1A-1L are cross section diagrams of a semiconductor process inaccordance with a first exemplary embodiment;

FIGS. 2A and 2B are cross section diagrams of a semiconductor process inaccordance with a second exemplary embodiment;

FIGS. 3A-3N are cross section diagrams of a semiconductor process inaccordance with a third exemplary embodiment;

FIGS. 4A-4D are cross section diagrams of a semiconductor process inaccordance with a fourth exemplary embodiment;

FIGS. 5A and 5B are cross section diagrams of a semiconductor process inaccordance with a fifth exemplary embodiment;

FIGS. 6A-6C are cross section diagrams of a semiconductor process inaccordance with a sixth exemplary embodiment;

FIG. 7 is a flow chart of a method in accordance with one exemplaryembodiment; and

FIG. 8 is a flow chart of a method in accordance with another exemplaryembodiment.

DETAILED DESCRIPTION

The following detailed description is merely illustrative in nature andis not intended to limit the embodiments of the subject matter or theapplication and uses of such embodiments. Any implementation describedherein as exemplary is not necessarily to be construed as preferred oradvantageous over other implementations. Furthermore, there is nointention to be bound by any expressed or implied theory presented inthe preceding technical field, background, brief summary, or thefollowing detailed description.

During the course of this description, like numbers are used to identifylike elements according to the different figures that illustrate thevarious exemplary embodiments.

The exemplary embodiments described herein may be fabricated using knownlithographic processes as follows. The fabrication of integratedcircuits, microelectronic devices, micro electro mechanical devices,microfluidic devices, and photonic devices involves the creation ofseveral layers of materials that interact in some fashion. One or moreof these layers may be patterned so various regions of the layer havedifferent electrical or other characteristics, which may beinterconnected within the layer or to other layers to create electricalcomponents and circuits. These regions may be created by selectivelyintroducing or removing various materials. The patterns that define suchregions are often created by lithographic processes. For example, alayer of photo resist material is applied onto a layer overlying a wafersubstrate. A photo mask (containing clear and opaque areas) is used toselectively expose this photo resist material by a form of radiation,such as ultraviolet light, electrons, or x-rays. Either the photo resistmaterial exposed to the radiation, or that not exposed to the radiation,is removed by the application of a developer. An etch may then beapplied to the layer not protected by the remaining resist, and when theresist is removed, the layer overlying the substrate is patterned.Alternatively, an additive process could also be used, e.g., building astructure using the photo resist as a template.

There are many inventions described and illustrated herein, as well asmany aspects and embodiments of those inventions. In one aspect, thepresent inventions relate to, among other things, methods ofmanufacturing a magnetoresistive-based device (for example, amagnetoresistive sensor or memory cell) having one or more electricallyconductive electrodes or conductors (hereinafter, collectively“electrode”) juxtaposed a magnetic material stack (for example, one ormore layers of magnetic materials and one or more layers of one or moretunnel barriers). In one embodiment, the methods of manufacturing employa plurality of hard masks (for example, two hard masks of the same ordifferent types) to form, define and/or pattern a magnetic tunneljunction (MTJ) device having one or more electrically conductiveelectrodes and the magnetic material stack. Notably, the MTJ device maybe, for example, a transducer (for example, electromagnetic sensor)and/or memory cell. As used herein, “hard” when used with “hard mask”means the ability to resist a particular etch.

In one embodiment, the hard masks (for example, metal and/or non-metalhard masks) may be relatively inert to the etch process of theelectrically conductive material(s) and magnetic material duringformation, definition and/or patterning of an electrically conductiveelectrode and magnetic material stack. For example, in one embodiment, afirst hard mask (for example, a metal hard mask) may be employed toform, define and/or pattern a first portion of the MTJ device (forexample, a first electrically conductive electrode and/or the magneticmaterial stack (or portion thereof). Such hard mask may include aselectivity, in connection with the etch processes (for example,chemical etch and/or mechanical etch processes), of the one or morelayers of electrically conductive materials that is greater than orequal to 10:1 and, in a preferred embodiment, includes a selectivitythat is greater than or equal to 20:1. The first hard mask may alsoinclude a selectivity in connection with the chemical etch and/ormechanical etch processes of the one or more layers of magneticmaterials that is greater than or equal to 10:1 and, in a preferredembodiment, includes a selectivity that is greater than or equal to20:1.

After forming, defining and/or patterning a first portion of the MTJdevice (for example, a first electrically conductive electrode and/orthe magnetic material stack (or portion thereof)), in one embodiment, asecond hard mask (which may comprise the same or different types and/ormaterials as the first hard mask) may be employed to form, define and/orpattern a second portion of the MTJ device (for example, a secondportion of the magnetic material stack and/or a second electricallyconductive electrode). In this regard, a second hard mask is definedover the partially formed or etched MTJ device to facilitate suitableetching or formation of the second portion of the MTJ device. The secondhard mask may be formed over and around the first portion of the MTJdevice thereby protecting and/or isolating such first portion to thesubsequent etch processes of the second portion of the MTJ device.

Notably, the manufacture of an MTJ device may employ more than two hardmasks during the forming, defining and/or patterning a portion of themagnetic material stack of the MTJ device.

In one embodiment, the hard mask includes silicon oxide and/or siliconnitride (for example, having a thickness range of about 500-2500Angstroms, and in a preferred embodiment, of about 1000-2000 Angstroms,and more preferred embodiment, of about 1250-1750 Angstroms). Inaddition thereto or in lieu thereof, the hard mask may include one ormore noble metals and/or alloy thereof, for example, alloys of a noblemetal with transition metals (for example, Platinum (Pt), Iridium (Ir),Molybdenum (Mo), Tungsten (W), Ruthenium (Ru) and/or alloy AB (whereA=Pt, Ir, Mo, W, Ru and B=Iron (Fe), Ni, Manganese (Mn)). In thisembodiment, the metal hard mask may include a thickness range of about5-200 Angstroms, and in a preferred embodiment, of about 10-200Angstroms, and more preferred embodiment, of about 20-100 Angstroms. Forexample, the metal mask may comprise PtMn or IrMn and include athickness range of, for example, 15-150 Angstroms or 20-100 Angstroms.

Notably, in another embodiment, the hard mask, after formation,definition and/or patterning of the magnetic material stack, may beretained on or over the magnetic material stack and thereafter employedas the electrically conductive electrode (or a portion thereto). Thatis, after formation, definition and/or patterning of the electricallyconductive electrode via etching of one or more layers of electricallyconductive materials, the hard mask (which includes a metal or highlyconductive material) is not removed but employed as the electricallyconductive electrode (or portion thereof). In this embodiment, thematerial of the hard mask is sufficiently conductive to function as anelectrically conductive electrode as well as sufficiently selective inconnection with the etch processes (for example, chemical etch and/ormechanical etch processes) of the one or more layers of magneticmaterials which form or define the magnetic material stack of themagnetoresistive-based device. For example, in one embodiment, the hardmask may comprise PtMn and/or IrMn—which are (i) electrically conductivealloys and (ii) relatively resistant to those certain etch processes ofone or more layers of magnetic materials (for example, conventionalfluorine and/or chlorine based etch processes) that form, define and/orprovide the magnetic material stack materials of themagnetoresistive-based device.

In yet another aspect, the present inventions relate to amagnetoresistive-based device (for example, sensor or memory cell havingone or more MTJ devices) and/or an array of magnetoresistive-baseddevices (for example, any array of sensors or memory cells, each havingone or more MTJ devices) manufactured (in whole or in part) using any ofthe techniques described and/or illustrated herein.

With reference to FIG. 1A (a cross-sectional view of a partially formedmagnetoresistive-based device disposed on a substrate 102), in oneembodiment, a hard mask layer 114 is deposited, grown, sputtered and/orprovided (hereinafter collectively “deposited” or various forms thereof(e.g., deposit or depositing)) on one or more layers 112 of electricallyconductive materials of an MTJ device. The hard mask layer 114 may bedeposited using any technique now known or later developed, for example,well known conventional techniques. In one embodiment, the hard masklayer 114 includes and/or consists of a silicon oxide, silicon nitrideand/or a material that is relatively inert to or during the etch processof one or more layers of electrically conductive materials (which, afterpatterning form the electrically conductive electrode 112′) and one ormore layers 110 of magnetic materials (which, after patterning form themagnetic material stack 106′—see FIG. 1J). For example, in oneembodiment, the hard mask layer 114 includes and/or consists of materialhaving a selectivity in connection with the chemical etch and/ormechanical etch processes of the one or more layers of electricallyconductive materials and/or magnetic materials that is greater than orequal to 10:1 and, in a preferred embodiment, includes a selectivitythat is greater than or equal to 20:1.

In one embodiment, the hard mask layer 114 includes a silicon oxideand/or silicon nitride (for example, having a thickness of about500-2500 Angstroms, in a preferred embodiment, having a thickness ofabout 1000-2000 Angstroms, and more preferred embodiment, having athickness of about 1250-1750 Angstroms). In another embodiment, the hardmask layer 114 includes and/or consists of one or more noble metalsand/or alloy thereof, for example, alloys of a noble metal withtransition metals (for example, Pt, Ir, Mo, W, Ru and/or alloy AB (whereA=Pt, Ir, Mo, W, Ru and B=Fe, Ni, Mn). In one embodiment, the metal hardmask layer 114 may include a thickness in the range of about 5-200Angstroms, and in a preferred embodiment, in the range of about 10-150Angstroms, and more preferred embodiment, in the range of about 20-100Angstroms. For example, a metal hard mask layer 114 may be comprised ofPtMn or IrMn and include a thickness range of, for example, 15-150Angstroms or 25-100 Angstroms. This embodiment is discussed in moredetail in connection with FIG. 3.

In yet another embodiment, the hard mask layer 114 includes siliconoxide and/or silicon nitride and one or more noble metals and/or alloythereof, for example, alloys of a noble metal with the aforementionedtransition metals. In this embodiment, it may be advantageous to disposethe non-metal material 202 (for example, silicon oxide and/or siliconnitride) on or over the one or more noble metals 201 and/or alloythereof so that the major surface exposed to the etching processconsists of silicon oxide and/or silicon nitride. (See FIG. 2A). Forexample, such a configuration may facilitate patterning of thephotoresist in those situations where the metal presents too reflectivea surface to suitably pattern the photoresist. Moreover, in thisconfiguration, the metal material is protected from significant aspectsof the etching processes and, as such, the integrity of the metalmaterial is substantially maintained or preserved and the metal materialmay thereafter be employed as the electrode 112′ or a portion thereof.Again, this embodiment is discussed in more detail in connection withFIG. 3.

After deposition of the hard mask layer 114 (FIG. 1B), a photo resist116 is deposited thereon and patterned to predetermined dimensionsconsistent with or correlated to selected dimensions of the electricallyconductive electrode 112′ to be formed (FIG. 1D). The photo resist 116may be deposited and patterned using any technique now known or laterdeveloped, for example, well known conventional deposition andlithographic techniques.

Notably, after initially patterning the photo resist 116, it may beadvantageous to “trim” the photoresist 116 and thereby adjust or shrinkthe size of at least a portion of the MTJ device 100 which is formed,defined and/or patterned using the hard mask 114. The trimming processmay also provide pattern fidelity (uniform edges of the bit) in additionto increasing the aspect ratio and smoothness. The photo resist 116 maybe trimmed using any technique now known or later developed, forexample, well known conventional trimming techniques. In one embodiment,a trim process may employ O2 or Cl2/O2 (1:1) or CF4/O2 (1:1) gases toshrink the resist. It may be advantageous to adjust the ratio of thegases and process time to obtain the desired size. Notably, other gasesmay be substituted for Cl2 and CF4 such as CHF3, CH2F2, etc.

With reference to FIG. 1C, the hard mask layer 114 is then etched, forexample, via mechanical etching (such as, for example, via sputteretching techniques) or chemical etching, to form or provide the firsthard mask 114′. Notably, the hard mask layer 114 may be etched, formedand/or patterned using any etchants and/or technique now known or laterdeveloped—for example, using conventional etchants and techniques (forexample, optical image end point techniques). It should be noted thatthe present inventions may employ any suitable materials and techniques,whether now known or later developed, to etch the hard mask layer 114and thereby form, define and/or provide the hard mask 114′. In oneembodiment, where the hard mask layer 114 includes a silicon oxideand/or silicon nitride (having a thickness of, for example, about 500A-2500 A), the hard mask layer 114 may be etched using a chemical etchprocess with F2 containing gases like CF4, CHF3, CH2F2 or Cl2 andcarrier gases such as Ar, Xe or a combination thereof. In anotherembodiment, where the hard mask layer 114 includes a metal (having athickness of, for example, about 50 A-100 A), the hard mask layer 114may be etched using sputter process with inert gases such as Xe, Ar, N2O2 gases or a combination thereof.

After forming or patterning the hard mask 114′ (having a predeterminedpattern which is at least partially defined by the patterned photoresist 116), it may be advantageous to remove or strip the photo resist116, for example, using conventional techniques. Here, by removing orstripping the photo resist 116 after the pattern is transferred to thehard mask layer 114, there is less likelihood that there will be loss ofbit or cell pattern (and, for example, the high aspect ratio) due to afailure of the photo resist 116 (for example, a “collapse” of the photoresist 116) during subsequent processing.

With reference to FIG. 1D, one or more layers of electrically conductivelayers 112 are then etched with the first hard mask 114′ “protecting”certain portions thereof, to form, define, pattern and/or provide theelectrically conductive electrode 112′. The one or more layers ofelectrically conductive layers 112 (for example, Tantalum (Ta),Tantalum-Nitride (TaN) or Ta—TaN composite) may be etched, formed and/orpatterned using any etchants and/or technique now known or laterdeveloped—for example, using mechanical etchants and techniques (forexample, sputter etchants and techniques) or chemical etchingtechniques. It should be noted that the present inventions may employany suitable etchants and techniques (for example, CF4, CHF3, CH2F2 incombination with inert carrier gases such as Ar or Xe), whether nowknown or later developed, to etch the one or more layers 112 ofelectrically conductive materials and thereby form, define and/orprovide the electrically conductive electrode 112′. Notably, in oneembodiment, a Ta, TaN or Ta—TaN composite electrically conductiveelectrode 112′ may include a thickness of about 50-1000 Angstroms.

After etching the one or more layers 112 of electrically conductivematerials and using the first hard mask 114′ to “protect” theelectrically conductive electrode 112′, the one or more layers 110 ofmagnetic materials are etched to form, define, pattern and/or provide afirst portion 111 of the MTJ device 100 (FIG. 1E). The one or morelayers 110 of magnetic materials (for example, Nickel (Ni), Iron (Fe),Cobalt (Co), Palladium (Pd), Magnesium (Mg), Manganese (Mn) and alloysthereof) may be etched, formed and/or patterned using any etchantsand/or technique now known or later developed—for example, usingmechanical and/or chemical techniques (for example, a low bias powersputter technique or a chemical etch technique such as a conventionalfluorine and/or chlorine based etch technique). Where the magneticmaterial stack 110′ includes one or more synthetic antiferromagneticstructures (SAF) or synthetic ferromagnetic structures (SYF) (FIG. 2B,the one or more layers of magnetic materials layers 110 may also includeone or more non-magnetic materials layers (204) (for example, Ruthenium(Ru), Copper (Cu), Aluminum (Al)). (See, FIG. 2B). Notably, one or moremagnetic material stack 110′ may include SAF and SYF structures, one ormore layers 110 of magnetic materials 203, and other materials(including magnetic 203 and/or non-magnetic 204) now known or laterdeveloped. Such materials and/or structures may be arranged in anycombination or permutation now known or later developed.

The etch process corresponding to the magnetic materials layers 110 ofthe first portion 111 of the MTJ device 100 (in this illustrative andexemplary embodiment, the magnetic materials layer(s) 110 disposed abovethe tunnel barrier layers) may be time controlled/monitored or endpointcontrolled/monitored. In one embodiment, the etch process of magneticmaterials layers 110 is stopped when the endpoint monitoring detects apredetermined material (for example, Magnesium (Mg) or Magnesium-Oxide(MgO)), for example, the material of the tunnel barrier 108, and/or theabsence of a predetermined material. In one particular embodiment, theetch process stops on top of the tunnel barrier 108. Here, monitoringthe endpoint for a rise in one or more of the tunnel barrier 108material signals in the plasma based on optical emission spectra (OES).A drop or rise in the OES signal for the tunnel barrier 108 or magneticmaterial stack 110′ above tunnel barrier 108 (immediately above or fewlayers above the tunnel barrier 108) may be monitored and, upondetection of signals corresponding to one or more tunnel barrier 108material(s), the etch process is terminated.

In one embodiment, the etch process is controlled by the endpointmonitoring and an over etch (percentage of the endpoint time or a fixedtime to end on the tunnel barrier 108). This control may be significantfor the electrical performance of the MTJ device 100 which may beaffected by oxidation of the tunnel barrier 108 due to an excessive overetch. For example, in one embodiment, a precise control may be achievedby having a relatively low sputter etch rate using Ar, Ar/O2, Xe, O2, ora combination of thereof, thereby providing an etch rate less than orequal to about 1 Angstrom/minute—and preferably, less than or equal to0.75 Angstroms/minute, and more preferably, less than or equal to 0.5Angstroms/minute.

Notably, the hard mask 114′ and electrically conductive electrode 112′are relatively unaffected during definition and/or patterning themagnetic material stack 110′. Here, the hard mask 114′ is relativelyinert to such processing and the hard mask 114′ “protects” the topsurface of the electrically conductive electrode 112′ (for example,particularly where such processing employs a mechanical etchtechnique—such as, low bias power sputter etch technique, due to thehard mask's sputter yield at those energies employed in connection withlow bias power sputter etch technique).

In one embodiment, after formation, definition and/or patterning of themagnetic materials 110 of the first portion 111 of the MTJ device 100,the hard mask 114′ may be removed or stripped using, for example,conventional techniques, to facilitate electrically contact to theexposed electrically conductive electrode. Indeed, after removing orstripping the metal hard mask 114′, the exposed electrically conductiveelectrode 112′ may be connected to sense, read and/or write conductorsand the magnetoresistive-based device completed using any processesand/or structures now known or later developed. In another embodiment,the hard mask 114′ is not removed or stripped but the MTJ device 100 maybe completed as described immediately above. As described in more detailbelow, where the hard mask 114′ comprises metal, the hard mask 114′ (orportion thereof) may be patterned and employed as the electricallyconductive electrode 112′.

Notably, after forming, defining and/or patterning a first portion ofthe MTJ device 100 (in this illustrative embodiment, an electricallyconductive electrode 112′ and a portion of the magnetic material layers110 disposed on the tunnel barrier 108) and before depositing the secondhard mask layer 118, it may be advantageous to “protect” the magneticmaterials of the first portion 111 of the MTJ device 100 as well as theinterface of such magnetic materials and tunnel barrier 108 fromsubsequent processing. In this regard, in one embodiment, an insulatingmaterial (not shown, for example, an aluminum oxide, magnesium oxide,titanium oxide, tantalum oxide, or any combination thereof) may bedeposited or formed on the side walls of the magnetic materials of thefirst portion of the MTJ device 100 and/or exposed surfaces or edges ofthe tunnel barrier 108 using any technique and/or materials now known orlater developed. For example, the materials and techniques described inU.S. Pat. No. 8,119,424 may be employed to protect the magneticmaterials of the first portion of the MTJ device 100 and exposedsurfaces or edges of the tunnel barrier 108 and thereby improve,maintain and/or enhance the integrity and/or uniformity (for example,across the MTJ device 100, the MTJ devices of the integrated circuit dieand/or the MTJ devices of the integrated circuit dice of the wafer) ofthe physical and/or electrical characteristics of the magnetic materialsof the first portion 111 of the MTJ device 100 and certain portions ofthe tunnel barrier 108 in light of subsequent processing.

With reference to FIGS. 1F-1H, after forming, defining and/or patterninga first portion 111 of the MTJ device 100, a second hard mask 118′ maybe employed to form, define and/or pattern a second portion 105 of theMTJ device (for example, a second portion 105 of the magnetic materialstack 106 and/or a second electrically conductive electrode 104′). Inthis regard, a second hard mask 118′ is defined over the partiallyformed or etched MTJ device 100 to facilitate suitable etching orformation of the second portion 105 of the MTJ device 100. The secondhard mask 118′ may be formed over and around the first portion 111 ofthe MTJ device 100 thereby protecting such first portion 111 to thesubsequent etch processes of the second portion 105 of the MTJ device100.

To that end, in one embodiment, a second hard mask layer 118 isdeposited, grown, sputtered and/or provided (hereinafter collectively“deposited” or various forms thereof (e.g., deposit or depositing)) onand over the first portion 111 of the MTJ device 100 and on the tunnelbarrier 108 of an MTJ device. The second hard mask layer 118 may bedeposited using any technique now known or later developed, for example,well known conventional techniques. In one embodiment, the hard masklayer 118 includes and/or consists of a silicon oxide, silicon nitrideand/or a material that is relatively inert to or during the etch processof one or more layers 104 of electrically conductive materials (which,after patterning form the electrically conductive electrode 104′) andone or more layers 106 of magnetic materials (which, after patterningform the magnetic material stack 106′ of the second portion 105 of theMTJ device 100).

The second hard mask layer 118 may include and/or consist of materialhaving a selectivity in connection with the chemical etch and/ormechanical etch processes of the one or more layers of electricallyconductive materials and/or magnetic materials that is greater than orequal to 10:1 and, in a preferred embodiment, includes a selectivitythat is greater than or equal to 20:1. For example, in one embodiment,the hard mask layer 118 includes a silicon oxide and/or silicon nitride(for example, having a thickness of about 500-2500 Angstroms, in apreferred embodiment, having a thickness of about 1000-2000 Angstroms,and more preferred embodiment, having a thickness of about 1250-1750Angstroms).

In another embodiment, the hard mask layer 118 may be a combination of asilicon oxide (for example, provided using tetraethylorthosilicate(TEOS)) and aluminum, magnesium, titanium, tantalum, or any combinationthereof. In this embodiment, after deposition of the aluminum,magnesium, titanium, tantalum, or any combination thereof, the siliconoxide is deposited, for example using TEOS whereby oxygen is absorbed bythe aluminum, magnesium, titanium, tantalum, or any combination thereofto from an aluminum oxide, magnesium oxide, titanium oxide, tantalumoxide, or any combination thereof, respectively, layer beneath thesilicon oxide. As noted above, this material may be useful in“protecting” the side walls of the magnetic materials of the firstportion 111 of the MTJ device 100 and/or exposed surfaces or edges ofthe tunnel barrier 108 during subsequent processing to form the MTJdevice 100. As noted above, the techniques described in U.S. Pat. No.8,119,424 may be employed to improve, maintain and/or enhance theintegrity and/or uniformity of the physical and/or electricalcharacteristics of the magnetic materials of the MTJ device 100 in lightof subsequent processing (for example, the etching processes to form thesecond portion 105 of the MTJ device 100).

After deposition of the second hard mask layer 118, a photo resist 120is deposited thereon and patterned to predetermined dimensionsconsistent with or correlated to selected dimensions of the secondportion 105 of the MTJ device 100 to be formed (FIG. 1G). The photoresist 120 may be deposited and patterned using any technique now knownor later developed, for example, well known conventional deposition andlithographic techniques. As noted above, after initially patterning thephoto resist 120, it may be advantageous to “trim” the photoresist 120and thereby adjust or shrink the size of at least a portion of the MTJdevice 100 which is formed, defined and/or patterned using the hard mask118′. The trimming process may also provide pattern fidelity (uniformedges of the bit) in addition to increasing the aspect ratio. The photoresist 120 may be trimmed using any technique now known or laterdeveloped, for example, well known conventional trimming techniques.

With reference to FIG. 1H, the second hard mask layer 118 is thenetched, for example, via chemical etching (for example, using chemicaletch process with gases CF4, CHF3, CH2F2 and carrier gases such as Arand Xe), to form or provide the second hard mask 118′. Notably, thesecond hard mask layer 118 may be etched, formed and/or patterned usingany etchants and/or technique now known or later developed—for example,using conventional etchants and techniques (for example, optical imageend point techniques). It should be noted that the present inventionsmay employ any suitable materials and techniques, whether now known orlater developed, to etch the second hard mask layer 118 and therebyform, define and/or provide the second hard mask 118′.

In one embodiment, the second hard mask 118′ is defined over and on thepartially formed or etched MTJ device 100 (in this illustrative example,the first portion 111 of the MTJ device 100) to facilitate suitableetching or formation of the second portion 105 of the MTJ device 100.The second hard mask 118′ may be formed over and around the firstportion 111 of the MTJ device 100 thereby protecting such first portion111 to the subsequent etch processes that form, define and/or patternthe second portion 105 of the MTJ device 100.

After forming or patterning the second hard mask 118′ (having apredetermined pattern which is at least partially defined by thepatterned photo resist 120), it may be advantageous to remove or stripthe photo resist 120, for example, using conventional techniques. Here,by removing or stripping the photo resist 120 after the pattern istransferred to the hard mask layer 118, there is less likelihood thatthere will be loss of bit or cell pattern (and, for example, the highaspect ratio) due to a failure of the photo resist 120 (for example, a“collapse” of the photo resist 120) during subsequent processing.

With reference to FIGS. 1H and 1I, the tunnel barrier layer(s) 108 arethen etched with the second hard mask 118′ “protecting” portions of thefirst portion 111 of the MTJ device 100 to form, define, pattern and/orprovide the tunnel barrier 108′. The tunnel barrier layer(s) 108 (forexample, Mg or MgO) may be etched and/or patterned using any etchantsand/or technique now known or later developed—for example, usingmechanical etchants and techniques (for example, sputter etchants andtechniques). It should be noted that the present inventions may employany suitable etchants and techniques, whether now known or laterdeveloped, to etch the one or more layers of electrically conductivematerials and thereby form, define and/or provide the tunnel barrier108′.

Thereafter, the one or more layers 106 of magnetic materials are etchedto form, define, pattern and/or provide a second magnetic materials 106′of the MTJ device 100 (FIG. 1J). The one or more layers 106 of magneticmaterials (for example, Ni, Fe, Co, Pd, Mg, Mn and alloys thereof) maybe etched, formed and/or patterned using any etchants and/or techniquenow known or later developed—for example, using mechanical and/orchemical techniques (for example, a low bias power sputter technique ora chemical etch technique such as a conventional fluorine and/orchlorine based etch technique). As stated above, the one or more layers106 of magnetic materials may include one or more syntheticantiferromagnetic structures (SAF) or synthetic ferromagnetic structures(SYF), the one or more layers 106 of magnetic materials layers may alsoinclude one or more non-magnetic materials layers (for example,ruthenium, copper, aluminum) (FIG. 2B). Notably, one or more magneticmaterial stack may include SAF and SYF structures, one or more layers ofmagnetic materials, and other materials (including magnetic and/ornon-magnetic) now known or later developed. Such materials and/orstructures may be arranged in any combination or permutation now knownor later developed.

The etch process corresponding to the magnetic materials layers 106 ofthe second portion of the MTJ device 100 may be timecontrolled/monitored or endpoint controlled/monitored. In oneembodiment, the etch process of magnetic materials layers 106 is stoppedwhen the endpoint monitoring detects a predetermined material,combination of materials and/or percentages. That is, the etch processterminates or stops on top of the electrically conductive layer(s) 104.

Similar to the process described above in relation to U.S. Pat. No.8,119,424, after the second magnetic materials 106′ of the MTJ device100 is formed, defined, patterned and/or provided, the second magneticmaterials 106′ of the MTJ device may be “isolated” or “protected” via anoxygen plasma which oxidizes any magnetic material remaining in thefield on top of the tunnel barrier 108′ to form a non-magneticinsulating oxide. This insulating oxide also protect the second magneticmaterials 106′ and thereby improve, maintain and/or enhance theintegrity and/or uniformity of the physical and/or electricalcharacteristics of the second magnetic materials 106′ of the MTJ device100 during the etch process of the electrically conductive layer(s) 104to form, define and/or pattern the bottom electrically conductiveelectrode 104′. Notably, the isolation and/or protection layer on thetunnel barrier 108′ and magnetic materials 106′ of the second portion105 of the MTJ device 100 may facilitate or allow etching processes thatemploy more “corrosive” gases like Cl2, BCl3, HCl, Br2, HBr, BBr3 (andcarrier gases such as Ar, Xe and N2) to etch the bottom electrode 104′.

With reference to FIGS. 1J and 1K, the one or more layers 104 ofelectrically conductive materials are then etched to form, define,pattern and/or provide the electrically conductive electrode 104′ of thesecond portion of the MTJ device 100—which, in this illustrativeembodiment, is the bottom electrode 104′ of the MTJ device 100. The oneor more layers 104 of electrically conductive materials (for example,Ta, TaN or Ta—TaN composite) may be etched, formed and/or patternedusing any etchants and/or technique now known or later developed—forexample, using chemical etchants and techniques (for example, chemicaletch process with gases Cl2, BCl3, HCl, Br2, HBr and/or BBr3 and carriergases such as Ar, Xe and N2). It should be noted that the presentinventions may employ any suitable etchants and techniques, whether nowknown or later developed, to etch the one or more layers of electricallyconductive materials 104 and thereby form, define and/or provide theelectrically conductive electrode 104′. Notably, in one embodiment, aTa, TaN or Ta—TaN composite electrically conductive electrode 104′ mayinclude a thickness of about 50-1000 Angstroms.

With reference to FIGS. 1K and 1L, in the event that the photo resist120 used to define or pattern the second hard mask 118′ is not removedearlier, after forming or patterning the electrically conductiveelectrode 104′ of the second portion 105 of the MTJ device 100, thephoto resist 120 may be removed or stripped, for example, usingconventional techniques. Indeed, any technique now known or laterdeveloped may be employed to remove or strip the photo resist 120.

As discussed above, in another embodiment, the first hard mask 114′ maybe a metal hard mask. In this embodiment, metal hard mask 114′, afterformation, definition and/or patterning, may serve as both the mask andthe electrically conductive electrode (or a portion thereto). Forexample, with reference to FIG. 3A (a cross-sectional view of apartially formed magnetoresistive-based device 300), in one embodiment,one or more layers 314 of metal materials are deposited on one or morelayers 310 of magnetic materials. The one or more layers 314 of metalmaterials include and/or consist of one or more materials that arerelatively inert to or during the etch process of one or more layers ofmagnetic materials (which, after patterning form the magnetic materialstack 310). For example, in one embodiment, the one or more layers 314of metal materials include and/or consist of materials having aselectivity in connection with the chemical etch and/or mechanical etchprocesses of the one or more layers of magnetic materials that isgreater than or equal to 10:1 and, in a preferred embodiment, includes aselectivity that is greater than or equal to 20:1.

The one or more layers 314 of metal materials may include and/or consistof one or more noble metals and/or alloy thereof, for example, alloys ofa noble metal with transition metals (for example, Pt, Ir, Mo, W, Ruand/or alloy AB (where A=Pt, Ir, Mo, W, Ru and B=Fe, Ni, Mn). Further,in one embodiment, one or more layers 314 of metal materials may includea thickness in the range of about 50-300 Angstroms, and in a preferredembodiment, in the range of about 75-250 Angstroms, and more preferredembodiment, in the range of about 100-200 Angstroms. For example, theone or more layers 314 of metal materials may be comprised of PtMn orIrMn and include a thickness range of, for example, 75-250 Angstroms or100-200 Angstroms.

After deposition of the one or more layers 314 of metal materials, itmay be advantageous to deposit photo-pattern assist layer 315 tofacilitate patterning of the photoresist 316 in those situations wherethe metal presents too reflective a surface to suitably pattern thephotoresist. In one embodiment, the photo-pattern assist layer 315 maybe a silicon oxide (for example, PECVD or CVD techniques usingtetraethylorthosilicate (TEOS)) or a silicon nitride. In this way, thephotoresist 316 may be readily patterned on the metal hard mask 314′.

After deposition of the one or more layers 314 of metal materials, aphoto resist 316 is deposited and patterned to predetermined dimensionsconsistent with or correlated to selected dimensions of the electricallyconductive electrode to be formed (FIG. 3B). Similar to the embodimentsillustrated in FIG. 1, the photo resist 316 may be deposited andpatterned using any technique now known or later developed, for example,well known conventional deposition and lithographic techniques.

Also, as noted above, after initially patterning the photo resist 316,it may be advantageous to “trim” the photoresist 316 and thereby adjustor shrink the size of at least a portion of the MTJ device 300 which isformed, defined and/or patterned using the hard mask 314′. The trimmingprocess may also provide pattern fidelity (uniform edges of the bit) inaddition to increasing the aspect ratio and smoothness. The photo resist316 may be trimmed using any technique now known or later developed, forexample, well known conventional trimming techniques. In one embodiment,a trim process may employ O2 or Cl2/O2 (1:1) or CF4/O2 (1:1) gases toshrink the photo resist 316. It may be advantageous to adjust the ratioof the gases and process time to obtain the desired size. Notably, othergases may be substituted for Cl2 and CF4 such as CHF3, CH2F2, etc.

With reference to FIG. 3C, in one embodiment, the photo-pattern assistlayer 315 is etched using the patterned photo-resist 316. In oneembodiment, the photo-pattern assist layer 315 may etched using achemical etch process with F2 containing gases like CF4, CHF3, CH2F2 orCl2 and carrier gases such as Ar, Xe or a combination thereof. Indeed,the patterned photo-resist 316 may be etched or removed using anytechnique now known or later developed.

In one embodiment, the patterned photo-resist 316′ is stripped orremoved and the metal hard mask 314′—electrically conductive electrode314′ is etched, formed and/or patterned using the photo-pattern assistlayer 315′ as a mask (FIGS. 3D and 3E). Here, the metal hard mask layer314 is etched, for example, via mechanical etching (such as, forexample, via sputter etching techniques) to form or provide the firsthard mask 314′. Notably, the metal hard mask layer 314 may be etched,formed and/or patterned using any etchants and/or technique now known orlater developed—for example, using conventional etchants and techniques(for example, optical image end point techniques). It should be notedthat the present inventions may employ any suitable materials andtechniques, whether now known or later developed, to etch the metal hardmask layer 314 and thereby form, define and/or provide the metal hardmask 314′. In one embodiment, where the metal hard mask layer 314includes a thickness of, for example, about 50 A-100 A, the hard masklayer 314 may be etched using sputter process with inert gases such asXe, Ar, N2 O2 gases or a combination thereof.

After forming the metal hard mask 314′—electrically conductive electrode314′ (having a predetermined pattern which is at least partially definedby the patterned photo resist 316 and the photo-pattern assist layer315′), it may be advantageous to remove or strip the photo-patternassist layer 315′, for example, using conventional techniques (FIG. 3F).Here, by removing or stripping the photo-pattern assist layer 315′ afterthe pattern is transferred to the metal hard mask layer 314, there isless likelihood that there will be loss of bit or cell pattern (and, forexample, the high aspect ratio) due to a failure of the photo resist 316(for example, a “collapse” of the photo resist 316) during subsequentprocessing.

With reference to FIGS. 3F and 3G, using the metal hard mask314′—electrically conductive electrode 314′, the one or more layers 310of magnetic materials are etched to form, define, pattern and/or providea first portion 311 of the MTJ device 300 in a manner similar to thatdiscussed above in connection with FIG. 1E. Here, the one or more layers310 of magnetic materials (for example, Ni, Fe, Co, Pd, Mg, Mn andalloys thereof) may be etched, formed and/or patterned using anyetchants and/or technique now known or later developed—for example,using mechanical and/or chemical techniques (for example, a low biaspower sputter technique or a chemical etch technique such as aconventional fluorine and/or chlorine based etch technique). Where themagnetic material stack 310′ includes one or more syntheticantiferromagnetic structures (SAF) or synthetic ferromagnetic structures(SYF), the one or more layers 310 of magnetic materials layers may alsoinclude one or more non-magnetic materials layers (for example,ruthenium, copper, aluminum) (FIG. 2B). Notably, one or more magneticmaterial stack 310′ may include SAF and SYF structures, one or morelayers 310 of magnetic materials, and other materials (includingmagnetic and/or non-magnetic) now known or later developed. Suchmaterials and/or structures may be arranged in any combination orpermutation now known or later developed.

As noted above, the etch process corresponding to the magnetic materialslayers 310 of the first portion of the MTJ device (in this illustrativeand exemplary embodiment, the magnetic materials layer(s) 310 disposedabove the tunnel barrier layers 308) may be time controlled/monitored orendpoint controlled/monitored. In one embodiment, the etch process ofmagnetic materials layers 310 is stopped when the endpoint monitoringdetects a predetermined material (for example, Mg or MgO), for example,the material of the tunnel barrier layer 308, and/or the absence of apredetermined material. In one particular embodiment, the etch processstops on top of the tunnel barrier layer 308. Here, monitoring theendpoint for an increase or decrease in one or more of the tunnelbarrier layer 308 material signals in the plasma based on opticalemission spectra (OES). An increase or decrease in the OES signal forthe tunnel barrier layer 308 or magnetic stack layer 310 above tunnelbarrier 308 (immediately above or few layers above the tunnel barrier308) may be detected/monitored and, upon detection of signalscorresponding to one or more tunnel barrier 308 material(s), the etchprocess is terminated.

In one embodiment, the etch process is controlled by the endpointmonitoring and an over etch (percentage of the endpoint time or a fixedtime to end on the tunnel barrier 308). This control may be significantfor the electrical performance of the MTJ device 300 which may beaffected by oxidation of the tunnel barrier 308 due to an excessiveoveretch. For example, in one embodiment, control may be achieved byhaving a low sputter etch rate using Ar, Ar/O2, Xe, O2, or a combinationof thereof, thereby providing an etch rate less than or equal to about 1Angstrom/minute—and preferably, less than or equal to 0.75Angstroms/minute and, more preferably, less than or equal to 0.5Angstroms/minute.

With reference to FIGS. 3H-3N, the remaining portion of the MTJ device300 may be manufactured in the same manner as described above inconnection with FIGS. 1F-1L. For the sake of brevity the discussion willnot be repeated.

Notably, in this embodiment, the material(s) of the metal hard mask314′—electrically conductive electrode 314′ are relatively unaffectedduring formation, definition and/or patterning the magnetic materialstack 310′. Here, the metal hard mask 314′—electrically conductiveelectrode 314′ is relatively inert to such processing and “protects”selected portions of the one or more layers 310 of magnetic materials,particularly where such processing employs a mechanical etchtechnique—such as, low bias power sputter etch technique, due to themetal hard mask's sputter yield at those energies employed in connectionwith low bias power sputter etch technique.

Moreover, after formation, definition and/or patterning of the magneticmaterial stack 310′, the resultant structure is an electricallyconductive electrode 314′ disposed on or over the magnetic material 310of the first portion 311 of the MTJ device 300 (FIG. 3G). Thus, in thisembodiment, after formation, definition and/or patterning of themagnetic material stack 310′, the metal hard mask 314′—electricallyconductive electrode 314′ is not removed or stripped and the exposedportions thereof may be connected to an electrical conductor (sense,read and/or write conductors) and the magnetoresistive-based devicecompleted using any processes and/or structures now known or laterdeveloped.

Thus, in this embodiment, the materials of the metal hard mask314′—electrically conductive electrode 314′ are sufficiently conductiveto function as an electrically conductive electrode as well assufficiently selective in connection with the etch processes (forexample, chemical etch and/or mechanical etch processes) of the one ormore the layers 310 of magnetic materials which form or define themagnetic material stack 310′ of the magnetoresistive-based device 300.For example, in one embodiment, the metal hard mask 314′—electricallyconductive electrode 314′ may comprise PtMn and/or IrMn—which are (i)electrically conductive alloys and (ii) relatively resistant to thosecertain etch processes of one or more layers of magnetic materials (forexample, conventional fluorine and/or chlorine based etch processes)that form, define and/or provide the magnetic material stack 310′materials of the magnetoresistive-based device 300.

There are many inventions described and illustrated herein. Whilecertain embodiments, features, attributes and advantages of theinventions have been described and illustrated, it should be understoodthat many others, as well as different and/or similar embodiments,features, attributes and advantages of the present inventions, areapparent from the description and illustrations. As such, the aboveembodiments of the inventions are merely exemplary. They are notintended to be exhaustive or to limit the inventions to the preciseforms, techniques, materials and/or configurations disclosed. Manymodifications and variations are possible in light of this disclosure.It is to be understood that other embodiments may be utilized andoperational changes may be made without departing from the scope of thepresent inventions. As such, the scope of the inventions is not limitedsolely to the description above because the description of the aboveembodiments has been presented for the purposes of illustration anddescription.

For example, although the present inventions have been described andillustrated as employing the second hard mask 118′, 318′ after etchingthrough the magnetic materials layer(s) 110, 310 (FIGS. 1E and 3G) andbefore etching the tunnel barrier layer(s) 108, 308, the manufacturingtechniques of the present inventions may employ a second hard mask 118′,318′ after etching the tunnel barrier layer(s) 108, 308 and therebyforming the tunnel barrier 108′, 308′. (See, for example, FIGS. 4A and4B). Note there are two tunnel barriers 108′, 308′, both positionedbetween magnetic materials 110′, 310′.

Further, although the present inventions have been illustrated asemploying only two hard masks, the present inventions may employ threeor more hard mask. (See, for example, FIGS. 4C and 4D). For example, inone illustrative embodiment, the first hard mask may be implemented asdescribed above in connection with the embodiments illustrated in FIGS.1 and 3 (first portion 432), the second hard mask may be employed todefine a tunnel barrier and magnetic materials of the second portion 434of the MTJ device, and a third hard mask may be employed to define atunnel barrier, magnetic materials and electrically conductive electrodeof a third portion 436 of the MTJ device. Further, in yet anotherillustrative embodiment, the first hard mask 114′, 314′ may beimplemented as described above in connection with the embodimentsillustrated in FIGS. 1 and 3, the second hard mask 118′, 318′ may beemployed to define two tunnel barriers 108′, 308′ and the magneticmaterials 110′, 310′ of the second portion 434 of the MTJ device, and athird hard mask 430 may be employed to define an electrically conductiveelectrode 104 of the third portion 436 of the MTJ device 400. Allpermutations and combinations are intended to fall within the scope ofthe present inventions.

It should be noted that one or more “soft” masks may be employed inconjunction with the two or more hard mask.

Moreover, it should be further noted, the patterned photo resist may bestripped or removed at multiple stages. For example, with reference toFIGS. 5A and 5B, in the metal hard mask—electrically conductiveelectrode 314 embodiment, the photo resist may be stripped or removedafter etching the metal hard mask—electrically conductive electrodelayers 314 which form or define the metal hard mask—electricallyconductive electrode 314. (Compare, FIGS. 3C-3F). Indeed, in anotherembodiment, the photo-pattern assist layer 315 is not stripped orremoved after etching the metal hard mask—electrically conductiveelectrode layers 314 to form or define the metal hard mask—electricallyconductive electrode 314′ (FIGS. 6A-6C).

Indeed, in one embodiment, a second or subsequent mask 118′, 318′ is notpatterned via a photolithography process. For example, in oneembodiment, the second or subsequent mask 118′, 318′ is formed via aself-aligning technique whereby the material of the second mask layer118, 318 is deposited and/or the characteristics of the features and/ormaterials of the MTJ device 100, 300 (which may be impacted bysurrounding structures, for example, neighboring MTJ devices of an arrayof MTJ devices) provide a self-aligning environment and the second orsubsequent mask 118′, 318′ is not patterned via photolithographyprocesses. As such, in this embodiment, the second/subsequent portion105, 305 of the MTJ device 100, 300 is not defined by aphotolithographically patterned second/subsequent mask 118′, 318′ (amask which is patterned via a photolithography process as describedabove—for example, as illustrated in FIGS. 1G and 1H or FIGS. 3I and3J).

Importantly, the present inventions are neither limited to any singleaspect nor embodiment, nor to any combinations and/or permutations ofsuch aspects and/or embodiments. Moreover, each of the aspects of thepresent inventions, and/or embodiments thereof, may be employed alone orin combination with one or more of the other aspects and/or embodimentsthereof. For the sake of brevity, many of those permutations andcombinations will not be discussed and/or illustrated separately herein.

FIGS. 7 and 8 are flow charts that illustrate exemplary embodiments of amethod of manufacturing a magnetoresistive-based device having amagnetic material layer formed over a first electrically conductivelayer, the magnetic materials layers including a tunnel barrier layerformed between a first magnetic materials layer and a second magneticmaterials layer. The various tasks performed in connection with methods700 and 800 may be performed by software, hardware, firmware, or anycombination thereof. For illustrative purposes, the followingdescription of methods 700 and 800 may refer to elements mentioned abovein connection with FIGS. 7 and 8. In practice, portions of methods 700and 800 may be performed by different elements of the described system,e.g., a processor, a display element, or a data communication component.It should be appreciated that methods 700 and 800 may include any numberof additional or alternative tasks, the tasks shown in FIGS. 7 and 8need not be performed in the illustrated order, and methods 700 and 800may be incorporated into a more comprehensive procedure or processhaving additional functionality not described in detail herein.Moreover, one or more of the tasks shown in FIGS. 7 and 8 could beomitted from an embodiment of the methods 700 and 800 as long as theintended overall functionality remains intact.

Referring to FIG. 7, the method 700 includes patterning a first hardmask over a second magnetic materials layer; removing the secondmagnetic materials layer unprotected by the first hard mask, to form asecond magnetic materials; patterning a second hard mask over the tunnelbarrier layer, the first hard mask, and sides of the second magneticmaterials; and removing the tunnel barrier layer and the first magneticmaterials layer unprotected by the second hard mask to form a tunnelbarrier and first magnetic materials.

The method 800 of FIG. 8 includes etching a portion of the secondmagnetic materials layer unprotected by a first hard mask to form asecond magnetic materials; patterning a second hard mask over the tunnelbarrier layer, the first hard mask, and sides of the second magneticmaterials; and removing the tunnel barrier layer and the first magneticmaterials layer unprotected by the second hard mask to form a tunnelbarrier and second magnetic materials, wherein the first hard maskcomprises a second electrode

Although the described exemplary embodiments disclosed herein aredirected to various magnetoresistive-based devices and methods formaking same, the present invention is not necessarily limited to theexemplary embodiments which illustrate inventive aspects of the presentinvention that are applicable to a wide variety of semiconductorprocesses and/or devices. Thus, the particular embodiments disclosedabove are illustrative only and should not be taken as limitations uponthe present invention, as the invention may be modified and practiced indifferent but equivalent manners apparent to those skilled in the arthaving the benefit of the teachings herein. Accordingly, the foregoingdescription is not intended to limit the invention to the particularform set forth, but on the contrary, is intended to cover suchalternatives, modifications and equivalents as may be included withinthe spirit and scope of the invention as defined by the appended claimsso that those skilled in the art should understand that they can makevarious changes, substitutions and alterations without departing fromthe spirit and scope of the invention in its broadest form.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any element(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature or element of any or all the claims. As used herein, the terms“comprises,” “comprising,” or any other variation thereof, are intendedto cover a non-exclusive inclusion, such that a process, method,article, or apparatus that comprises a list of elements does not includeonly those elements but may include other elements not expressly listedor inherent to such process, method, article, or apparatus.

While at least one exemplary embodiment has been presented in theforegoing detailed description, it should be appreciated that a vastnumber of variations exist. It should also be appreciated that theexemplary embodiment or exemplary embodiments are only examples, and arenot intended to limit the scope, applicability, or configuration of theinvention in any way. Rather, the foregoing detailed description willprovide those skilled in the art with a convenient road map forimplementing an exemplary embodiment of the invention, it beingunderstood that various changes may be made in the function andarrangement of elements described in an exemplary embodiment withoutdeparting from the scope of the invention as set forth in the appendedclaims.

What is claimed is:
 1. A method of manufacturing a magnetoresistivedevice from a magnetoresistive stack including (I) a first regionincluding one or more layers of ferromagnetic materials disposed above afirst electrically conductive material, wherein the first region formsone of a magnetically fixed layer or a magnetically free layer of themagnetoresistive device, (II) an intermediate layer disposed above thefirst region, (III) a second region including one or more layers offerromagnetic materials disposed above the intermediate layer, whereinthe second region forms the other of the magnetically fixed layer or themagnetically free layer of the magnetoresistive device, and (IV) asecond layer of electrically conductive material disposed above thesecond region, method comprising: (a) patterning a mask above a portionof the second layer of electrically conductive material; (b) after step(a), forming one or more sidewalls on the magnetoresistive stack byetching through (i) the second layer of electrically conductivematerial, (ii) the second region, (iii) the intermediate layer, and (iv)the first region; (c) after step (b), providing an insulating materialon or over the formed one or more sidewalls; and (d) after step (c),connecting the first layer of electrically conductive material to afirst electrical conductor and connecting the second layer ofelectrically conductive material to a second electrical conductor. 2.The method of claim 1, wherein the mask is a metal hard mask and theintermediate layer forms a tunnel barrier of the magnetoresistivedevice.
 3. The method of claim 1, wherein the mask includes one or moremetals comprising at least one of the elements selected from the groupconsisting of Pt, Ir, Mo, Ru, and alloy AB where A comprises Pt, Ir, Mo,W, Ru, and B comprises Fe, Ni, and Mn.
 4. The method of claim 1, whereinthe mask includes PtMn or IrMn.
 5. The method of claim 1, wherein themask is a metal hard mask, and wherein connecting the second layer ofelectrically conductive material to a second electrical conductorincludes connecting at least a portion of the metal hard mask to thesecond electrical conductor.
 6. The method of claim 1, wherein step (a)includes etching the mask using mechanical etching.
 7. The method ofclaim 1, wherein step (a) includes etching the mask using sputteretching.
 8. The method of claim 1, further including, before step (d),removing the mask to expose the second layer of electrically conductivematerial.
 9. The method of claim 1, wherein the insulating materialincludes at least one of a silicon oxide, silicon nitride, andtetraethylorthosilicate (TEOS).
 10. The method of claim 1, wherein thefirst region and/or the second region includes one of a syntheticantiferromagnetic structure (SAF) or a synthetic ferromagnetic structure(SYF).
 11. The method of claim 1, wherein the first region and/or thesecond region further includes one or more layers of nonmagneticmaterials.
 12. The method of claim 1, further including, after step (b),subjecting the one or more sidewalls to an oxidation process.
 13. Themethod of claim 1, further including, after step (b), exposing the oneor more sidewalls to an oxygen plasma.
 14. A method of manufacturing amagnetoresistive device from a magnetoresistive stack including (I) afirst region including one or more layers of ferromagnetic materialsdisposed above a first electrically conductive material, wherein thefirst region forms one of a magnetically fixed layer or a magneticallyfree layer of the magnetoresistive device, (II) an intermediate layerdisposed above the first region, wherein the intermediate layer forms atunnel barrier of the magnetoresistive device, (III) a second regionincluding one or more layers of ferromagnetic materials disposed abovethe intermediate layer, wherein the second region forms the other of themagnetically fixed layer or the magnetically free layer of themagnetoresistive device, and (IV) a second layer of electricallyconductive material disposed above the second region, method comprising:(a) patterning a mask above a portion of the second layer ofelectrically conductive material; (b) after step (a), forming one ormore sidewalk on (i) the second layer of electrically conductivematerial, (ii) the second region, (iii) the intermediate layer, and (iv)the first region, by etching through a thickness of the magnetoresistivestack; (c) after step (b), subjecting to an oxidation process, at leastsome of the formed one or more sidewalk of (i) the second layer ofelectrically conductive material, (ii) the second region, (iii) theintermediate layer, and (iv) the first region; and (d) after step (c),etching through the first layer of electrically conductive material. 15.The method of claim 14, wherein step (c) includes oxidizing magneticmaterial formed on the one or more sidewalls of the intermediate layerafter step (b).
 16. The method of claim 14, wherein the oxidationprocess of step (c) includes plasma oxidation.
 17. The method of claim14, further including, after step (c), providing an insulating materialon or over at least some of the formed one or more sidewalls of (i) thesecond layer of electrically conductive material, (ii) the secondregion, (iii) the intermediate layer, and (iv) the first region.
 18. Themethod of claim 14, further including, after step (d), connecting thefirst layer of electrically conductive material to a first electricalconductor and connecting the second layer of electrically conductivematerial to a second electrical conductor.
 19. The method of claim 14,wherein the first region and/or the second region includes one of asynthetic antiferromagnetic structure (SAF) or a synthetic ferromagneticstructure (SYF).
 20. The method of claim 14, wherein step (b) includesetching through a thickness of the magnetoresistive stack using sputteretching.